Diaphragm signal



July 30, 1929. P. H. WiTHINGTON DIAPHRAGH SIGNAL Filed Jan. 22, 1924 EEII! lzllmg I'll! III .III

\ .5. 55:15:45,154"lav I Patented July 30, 1929.

1 UNITED STATES PATENT OFFICE.

PHILIP H. WITHDI'GTON, OF CLEVELAND, OHIO, ASSIGNOBTO THE SPAB-KS-WITHING- TON COMPANY, OF JACKSON, MTCHIGAIN, A CORPORATION OF OHIO.

DIAPHRAGM SIGNAL.

Application filed January 22, 1924. Serial No. 687,879.

This' invention relates to a new and imroved diaphragm signal, and more particuarly to the specific form and construction of the diaphragm thereof. l The main object of the invention is to effect a substantial saving of the material, such as steel, of which the diaphragm is formed,

without materiall aflectin the rigidity with which the diaphragm is clamped between and secured to the edges of the diaphragm case sections.

Further, with this construction, buckling of the. dia hragm ordinaril; caused by the fact that the clamping surfaces are not abso- 1 lutely flat, is limited to a considerable extent by reducing the area and eliminating the' continuity of the clamping surfaces.

Further, the fact that a com aratively small area of the edge of the diaphragm is clamped between the case sections permits the dia hragm to flex more easily.

Anot er advantage relates to the particular disposition of the contact surfaces of the diaphragm .wear-piece with respect to certain of the bolt holes through which the usualclamping bolts extend. 3 Other ob'ects and advantages relate to the details of form and consfi'uction of the apparatus, all as will more fully appear from the following description, taken in connection with the accompanying drawings, in which:

F re 1 is an elevation of the dia hragm and imt case section of the signal i lustrating theclamping bolts.

Figure 2 is a longitudinal section of a portion of the signal.

Figure 3 illustrates the method of blanking the diaphragm from a strip of sheet metal.

In general form, the signal here illustrated is of a well known type and construction embodying a rear case section --1 of dished form, and a front case section -2- of oppositely dished form, the edges or peripheries of the case sections being substantially flat and ada ted to receive between them the edge of a diaphragm 3;preferably formed of sheet steel. One of the case sections, as 2--, is provided with a circumferential flange 30- that en ages the edge of the diaphragm and the e ge of the other case section 1 when the parts are assembled.

In thewell known construction of diaphragm signals, the edge of the diaphragm is preferably separated from the clamping peripheries of the case sections 1 and 2- washers 4'. Clamping bolts are provided extending thru the peripheries of the case sections and thru openings in the edge of the diaphragm and thru the clamping washers 4-. As here shown, four. of such bolts are used in the present construction of horn, and are positioned in a special manner erably as shown portions of the circumfer-- ence of the same circle, such circle having a diameter substantially equal to the internal diameter of the flange 30 so that the dia hragm will fit within the flange 30- wit the arcuate edge with the opposite flat e ge portions of the case sections -1- and 2-. The straight sides which, as illustrated, are in the position of the bases of segments of the circle of which the arcuate sides form a part, are arranged between the arcuate sections, and are numbered -8, -9, 10 and 11 and the straight sides -8 and 10-- are diametrically opposite each other, while the straight sides 9 and 11 are diametrically opposite each other, and the two diameters are preferably approximately perpendicular to each other.

The bolt openings for the reception of the bolts 12, "13, -14 and 15 are positioned in a special manner to effect the most advantageous results, and as here shown, the openings for the reception of the bolts -12. and -14-- are formed in arcuate sides 4 and 7- a j cent the oppoby means of cork or other suitable ortions in contact site ends respectivel' of the flat side 8- and the openings or receiving the bolts -13 and 15 are formed in the arcuate sides and 6 adjacent the opposite ends of the straight side The diaphragm 3- is further provided with an openin 17, for the reception of a positioning pin 18 rigidly carried by one of the case sections as 2-.

The diaphragm'is further provided with the usual Wear piece 19 which in this illustration is positioned in a novel manner in that its opposite inclined sides 20 and -2l are in alignment with the openings for receiving two oppositely disposed bolts as the bolts 12 and -l5-, altho the alignment might be with the bolts -13- and 14- and this for the purpose of applying the strain produced by forced vibration of the diaphragm by contact of cam -22 with wear piece -19 directl across the diameter of the diaphragm w ich intersects two clamping bolts so as to insure rigidity and permanent securement of the diaphragm in a tight and proper manner to afford the most effective sound production.

In Figure 3 the method of blanking this diaphragm is illustrated, and it will be noted that this diaphragm may be blanked from a strip 24-'- of substantially less Width than the strip required to blank a circular diaphragm having a radius equal to the radius of the arcuate sides 4-, 5, 6 and -7-. Further, a reater number of diaphragms can be blan ed from a strip of the same length, and thus a material saving in sheet metal which is perhaps the most expensive material used in signal production, is effected.

The rear case section -1- may in the usual manner carry a casing 23 which encloses the driving parts for the cam 22.

Altho I have shown and described a specific form and construction of device as constituting a preferred embodiment of my in.- vention, I do not desire to restrict myself to the exact details of form, or for instance, the exact position of the bolt holes, as various 2. In a signaling device, a diaphragm case. section having a flat edge portion, a dia-' phragm adapted to rest against the said flat edge portion, and having arcuate ed e portions of substantially the same radius of curvature, and constituting portions of a circle of a diameter substantially equal to the external diameter of the fiat edge portion of said case section, said arcuate edge portions being spaced by straight portions constituting substantially the bases of segments of the circle defined by the arcuate edge portions.

3. A diaphragm formed of a steel sheet substantially in the form of a polygon with alternate edges substantially straight and bolt-receiving openings wholly within the edge of the diaphragm between the alternate substantially straight sides. I

4. A diaphragm formed of a steel sheet substantially in .the form of a polygon with alternate edges substantially straight and bolt-receiving openings wholly Within the edge of the diaphragm adjacent the opposite ends of each of the alternate straight sides.

5. A diaphragm formed of a steel sheet of substantially octagonal form and with y hand this 31st day of December, 1923.

PHILIP H. WITHENGTON, 

